1. Field of the Invention
The present invention relates to a system for incinerating substances, and more particularly, to a combustion system suitable for incinerating non-industrial wastes and industrial wastes.
2. Description of the Related Art
Incineration of a substance is usually carried out by means of a high-temperature oxidative reaction between oxygen contained in air and the substance, and therefore the presence of oxygen-containing air is indispensable for combustion. Air surrounding the planet has been considered to be formed during the course of a long history of evolution from the Genesis era. The era at which air has become substantially equal in composition to that at the present time, particularly, the time when the oxygen content of air substantially reached its current level, is not known with certainty. At least in terms of atmospheric composition, it is believed that there is not much difference between air that existed at the time when human beings emerged and air that exists now. Primitive men should have observed, as one type of natural phenomenon, combustion in such forms as spontaneous ignition typified by a forest fire. Combustion per se is a natural phenomenon which has been well known since time immemorial. Since primitive man mastered fire, which is considered to have taken place far back into the prehistoric period, the techniques for mastering fire have probably been utilized actively, as combustion method, for the sake of our lives.
A conventional combustion system is designed so as to effect an oxidative reaction by utilization of oxygen contained in the air, and is provided with means for supplying sufficient oxygen or air to a combustion furnace. In some cases, a proper amount of fuel is added to the furnace in order to efficiently incinerate substances to be combusted, as needed. An air outlet section is further formed in the combustion furnace, and, for example, an exhaust gas is delivered from the air outlet section to a cooling chamber where solid residues are eliminated from the gas. The resultant gas is exhausted from a chimney. In effect, various types of combustion systems or incinerators are available; e.g., a total continuous feed incinerator, a quasi-continuous feed incinerator, a mechanical batch feed incinerator, and a fixed batch feed incinerator.
Although the majority of substances are completely burned during the course of combustion and are converted to stable oxides, some of the substances are incompletely burned and yield various types of volatile, less-volatile, and nonvolatile products. For example, when organic substances, such as ordinary organic compounds, are completely burned, water and carbon dioxides are largely produced. More specifically, when cellulose which is the principal constituent of paper or soybean oil is completely burned, water and carbon dioxides are produced. In contrast, if the cellulose or soybean oil is incompletely burned, various types of unburned substances, e.g., carbon monoxides, aldehyde, and soot are exhausted and a polynuclear aromatic compound, such as pyrene, is produced from the cellulose. Tobacco smoke and exhaust gas from a car are also known to contain various types of products resulting from incomplete combustion.
Unburned products contain substances deleterious to the global environment or human health. Particularly, toxic substances which are also known as environmental hormones act as endocrine disturbing chemicals, such as dioxin, are produced in an incinerator as a result of incineration of wastes at insufficient temperatures. Serious environmental pollution caused by such toxic substances have recently been considered a global social problem. All the countries of the world, including Japan, are required to take immediately measures against such pollution.
In light of the present situation set forth, the object of the present invention is to provide a combustion system which completely burns substances to be incinerated, particularly, non-industrial wastes and industrial wastes, without involvement of generation of harmful substances.